A field chopper basically has a normally automotive frame adapted to travel along the ground in a normal travel direction and having a front end provided with an intake device, some element that cuts a standing crop. A conveyor displaces the cut crop back on the frame to a chopper which is typically constituted as a large bladed drum. The chopped crop is typically then blown through a chute to a takeoff vehicle, for instance a large wagon towed alongside the chopper.
In the machine sold as model E280 by VEB Kombinat Fortschritt Landmaschinen the chopping unit is fixed on the machine frame and the intake device is suspended so that it can move up and down relative to this frame, thereby accurately following the ground and cutting the crop as low as possible. When the intake unit is very long and wide the output end of this unit can move quite a lot relative to the following conveyor and/or chopper. As a result transfer at this location is inefficient and can even lead to significant loss of crop.
It is possible to separate the chopping drum and the downstream conveyor as described in West German patent document No. 2,438,361 and to make the chopper unit movable in the vehicle frame. The chopper unit moves with the intake device in this case so there are no transfer problems between these subassemblies. On the other hand, however, there are transfer problems between the chopping unit and the output blower, so that this conveyor must be overdimensioned to do its job, once again wasting energy.
The machine sold as model Jaguar 690/675 by Firma Class OHG is a variation on this system wherein the chopping drum is also a conveyor fan. Since here also the output opening or chute does not move with the chopper/conveyor drum it is necessary to provide an auxiliary conveyor in the output chute to prevent the machine from jamming.